Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 5 (ENGINE CONTROLS - SELF-DIAGNOSTICS - 8.1L)INSPECTION/MAINTENANCE PROCEDURESINSPECTION/MAINTENANCE CATALYST SYSTEM SET PROCEDUREDIAGNOSTIC PROCEDURES
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8
Diagnostic Procedures
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Diagnostic Procedures
WARNING: This page is about a different variant/trim than selected.
- Perform inspection/maintenance system check. See INSPECTION/MAINTENANCE SYSTEM CHECK . After performing inspection/maintenance system check, go to next step.
- Ensure vehicle meets the specific conditions before performing procedure. See CONDITIONS FOR RUNNING . Turn off all accessories (e.g., A/C, blower fan, etc.). Start engine and allow to idle for 2 minutes. Accelerate vehicle at part throttle to 55 MPH and maintain speed for 5 minutes. Decelerate to a complete stop. Operate engine at idle for 2 minutes while service brake is depressed, A/T in Drive or M/T in Neutral with clutch pedal depressed. Using scan tool, observe I/M SYSTEM STATUS display. If catalyst system status updates to YES, go to step 5. If catalyst system status does not update to YES, go to next step.
- Using scan tool, observe DTC INFO. If any DTCs are set, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are set, go to next step.
- Using scan tool, observe the NOT RAN SINCE CODE CLEARED display to determine if DTCs P0420 or P0430 have run. Determine which of the DTCs required for a YES status that have not run. Enter DTC in SPECIFIC DTC menu on scan tool. Operate vehicle within conditions under CODE ENABLE CRITERIA for the specific DTC to run. Repeat procedure until scan tool indicates that diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Using scan tool, observe I/M SYSTEM STATUS display. If status updates to YES, go next step. If status does not update to YES, see DIAGNOSTIC AIDS .
- Using scan tool, observe emission related DTC portion of I/M SYSTEM STATUS display. If scan tool indicates any emission related DTCs, diagnose affected DTCs. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
WARNING:
Road test vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.